A multi-hop relay is a measure executed when a network has no fixed access points, which is first researched and applied in an adhoc network. An adhoc network has no fixed infrastructure and no fixed routers, in which all nodes are mobile and all the nodes can keep contact with other nodes in a random mode dynamically. All nodes are equal in the network, and no central control node needs to be set. The node in the network not only has functions needed by an ordinary mobile station (MS), but also has a packet forwarding capability. In such an environment, due to the limitation of wireless coverage of the MS, two user MSs that are incapable of direct communication can perform packet forwarding through other nodes, which is referred to as multi-hop communication. In recent years, the multi-hop relay technology is applied in the conventional cell network, and the establishment of a new-type cell multi-hop network also becomes a new research focus in the wireless communication. In a cell multi-hop network, an MS can be connected to a corresponding cell base station (BS) through one or more relay nodes. The use of the relay nodes decreases a path loss and improves communication quality of each transmission link, so that capacity and coverage of the entire cell of origin are greatly increased. In the cell multi-hop network, it is very important for performance improvement of the entire system to find suitable relay nodes, and therefore an effective routing algorithm is required.
A method for sending packet data in the prior art is described as follows. In consideration of a feature that a cell multi-hop network is centered on the BS, a conventional distributed routing mode is changed into a centralized processing mode that the BS provides routing for each node in a unified mode. The BS maintains statuses of links among all MSs, and selects paths for communication of the MSs in a centralized mode according to the maintained link statuses. Through the centralized processing mode, the BS can gradually obtain a topological structure of the cell by processing and maintaining information acquired in the routing process.
In addition, in consideration of a two-hop access cell, when a relay is needed as the quality of a link between the MS and the BS is deteriorating, a relay request is first sent to the BS to require the BS to provide a multi-hop routing. If the BS cannot find the path, the MS broadcasts a relay-request routing signal to nearby nodes. After receiving the relay request, an intermediate node returns a signaling to the BS. Therefore, the BS can obtain quality of a first-hop link and measure quality of a second-hop link. Thus, every time a relay request response sent by an intermediate node is received, the BS updates its own channel quality matrix once. After the channel quality matrix is completely updated, the BS executes the routing algorithm again. At this time, the BS has obtained all channel information related to the MS, so that a relay node is selected and the selected relay node is returned to the MS as a feedback, so as to enable the MS to send packet data through the relay node.
During the research of the prior art, the inventor finds that by using the method for sending packet data in the prior art, a relay request needs to be sent for packet relay distribution each time and the BS perform all the link processing, This results large resource overhead of the BS and high communication complexity.